[Neuroendocrine tumor of the extrahepatic bile ducts. Case report and literature review].

Neuroendocrine neoplasms (NENs) are heterogeneous tumors with a common phenotype. There are two fundamentally different groups of NENs: well differentiated with a low proliferative index, called neuroendocrine tumors (NETs) and poorly differentiated with a high proliferative index, called neuroendocrine carcinoma (NEC). Extrahepatic bile duct NETs (EBNETs) account for 0.2% to 2% of all gastrointestinal NETs and up to 2% of all malignant neoplasms of the extrahepatic bile ducts. To date, 114 cases of EBNETs have been described, with disease-free survival ranging from 2 to 240 months. In most cases, the tumors expressed Chromogranin A, Synaptophysin, CD56, and NSE. This report presents a rare case of an EBNET in a 61-year-old patient following resection of the extrahepatic bile ducts. The description includes data from radiological and ultrasound diagnostic methods, macro- and microscopic characteristics of the tumor, and immunohistochemical profile.